Moravian C3-61000Pro
The Sony IMX455 backside illuminated CMOS-sensor is a very popular full-frame sensor. It has a pixel-size of 3.8 µm and impressive 61MP resolution. Moravian has built this sensor in its C3 line of cameras and refers to it as the C3-61000. Moravian cameras stand out through their top-notch build quality and focus on reliability. The whole body and filter wheel is machined from aluminium. The C3-cameras have a mechanical shutter to keep dust away from the sensor, and to take dark-frames without having to cover the telescope. The cooling mechanism with two cooling fans is pretty strong and capable of cooling the sensor to 40°C below ambient.
The sensor of the C3-61000 has a true 16-bit readout and a large full-well depth of 51ke. This gives the system an impressive 14 stops dynamic range. The camera is available in two versions, the regular and the ‘Pro’ version. The only difference is the reliability of the sensor. The Pro version includes the so-called ‘industrial grade’ sensor, classified for more than 300h of use per year. The mechanical shutter, industrial grade sensor, and general high build quality make it a great camera for a remote observatory, where reliability is so important
Specifications
Resolution: 9576*6388 pixels (61 Megapixels)
Sensor-size: 36 x 24mm; 43.3mm diagonal
Quantum Efficiency: 91%
Full well capacity: 51.4ke; ADC: true 16-bit
Gain range: 0-4030; High Conversion Gain: 2750
Power consumption: 8W (no cooling) - 47W (max cooling)
Dimensions (without filterwheel): 154 x 154 x 65 mm
Weight (incl filterwheel “M”): 2.5 kg
Mechanical Shutter
The C3-61000 has a mechanical shutter, which protects the sensor from dust. Also, with the shutter closed, dark frames can be collected without having to cover the telescope. The camera connector comes with an integrated tilt adjustment mechanism. It is available in many configurations, allowing it to fit many imaging trains. The example here is fitted with an M68 fitting.
Integrated Filterwheel
The C3 monochrome cameras come with an integrated filterwheel. For filters up to 36mm in diameter, this can be integrated in the square housing of the camera. For larger filters, the filterwheel is contained in a round housing that is screwed onto the camera. A small dedicated RJ-11 based cable ensures powering of the wheel and communication between the wheel and the camera.
Chroma Filters
For the full frame sensor, the filterwheel is equipped with a set of seven round 50mm unmounted Chroma filters. They include the Luminance, Red, Green and Blue broadband filters, as well as H-alpha, Oxygen-III and Sulfur-II narrowband filters with 3nm bandwidth. The filters are placed at the back, facing the camera. They are held in place with three little screws, without any filter-masks.
Centerplate
The C3 camera system allows for quite some customisations. Different sizes of (semi)integrated filterwheels, different cooling options, optional ethernet connectivity, etc. One purely cosmetic option is the choice of color for the camera center plate. Default is black, but you can opt for a blue or red option. Here blue is chosen to match the CDK14 telescope it will be attached to.
Build Quality
The build quality of the Moravian cameras is top-notch. The whole body is made of machined aluminium. This gives a lot of structural strength to the body, which gives some interesting options for connecting add-ons. The top of the camera has four M4 holes and two 1/4” holes. A vixen-style dovetail is one of the accessories available to make use of this connectivity.
Balancing weights
Large filterwheels like those on full-frame systems, create a challenge for balancing. Their asymmetric weight distribution makes balancing the ‘Z-axis’ difficult, especially when the camera can rotate. Therefore I have opted to equip the camera with four 200g balancing weights screwed into the 1/4” connection points on the camera. The weight distribution is now always the same, no matter the rotation of the camera.